Synchronizing clutch mechanism



Oct. 31, 1939. E. A. THOMPSON 2,177,964

SYNCHRONIZ ING CLUTCH MECHANISM NOV. 9,' 3 t S t l W 5 3 Q Q\ g I I 1 3 L a I g Ir 8 g H NR EN Snventor fail Q Twin 25022 Oct. 31, 1939. E; A, THOMPSON 2,177,964

SYNCHRONI ZING CLUTCH MECHANISM Original F iled Nov. 9, 1935 s Sheets-Sheet s 3noentor r attorneys.

Patented Oct. 31, 1939 UNITED STATES SYNCHRONIZIN G CLUTCH MECHANISM Earl A. Thompson, Birmingham, Mich., assignor to General Motors Corporation, Detroit, Mich.,

a corporation of Delaware Original application November 9, 1935, Serial No.

48,971. Divided and 1937, Serial No. 148,852. 1936 9 Claims.

This application is a division of United States application Serial No. 48,971, Patent No. 2,101,826. The invention disclosed herein relates to mechanism for operating frictional and positive synchronizing clutches, more particularly synchronizing clutches of the inertia check type disclosed in the parent application.

The object of the invention is to multiply the force received by the ratio change lever and transmit the force to the movable elements of a synchronizing clutch increased to such a degree that the friction clutch elements may be engaged with suflicient pressure to insure synchronization within the brief interval of time consumed in changing ratios in a moving motor vehicle.

The invention consists of a power transmitting synchronizing clutch control mechanism of high mechanical advantage whereby powerful synchronizing effort may be applied to the friction elements, and relaxed before engagement of the positive elements, said means comprising specifically roller cam mechanism operatively disposed between a shift rail for second and third speed trains and a cam-equipped lever to which the shifter yoke that imparts movement to the slidable coupling element is secured.

In the accompanying drawings wherein like reference characters indicate like parts throughout the several views;

Fig. 1 is an elevation of a transmission casing partly broken away and exposing inclosed change gear mechanism;

Fig. 2 is a cross section on line 22 of Fig. 1.

Fig. 3 is a view from the right-hand side of Fig. 2 disclosing the control mechanism partly in longitudinal section.

Fig. 4 is a diagrammatic view illustrating the manner in which parts of the mechanical advantage mechanism operate and shows the first and second positions of that mechanism during the first moiety of the shifting operation.

Fig. 4a is a diagrammatic view of the parts shown in Fig. 4 in third and fourth positions during the second moiety of the shifting operation, and

Fig. 5 is a cross section on-line l0lll of Fig. 3.

'In the drawings numeral I2a indicates a transmission casing, the upper part of which is closed by a cap 13a. The power delivering end of an input shaft 20 enters the front of the casing and is rotatable in a bearing not shown. The end of shaft 20 within the casing is equipped with a countershaft driving gear 22 which has integrally or otherwise joined to its rear face an annular rearward-trendingadjunct 24 carrying internal this application June 18, In Canada May 15,

gear-like clutch teeth 26 and formed with an external conical friction clutch surface 28. The series of clutch teeth 26 constitute with said adjunct 24 a positive clutch element and said adjunct with its conical clutch surface constitutes a friction clutch element which is combined with axially movable positive and friction clutch elements to constitute a synchronizing coupling means to couple the transmission mechanism to operate in third or high speed ratio.

A main driven shaft 30, commonly designated the spline shaft in motor vehicle nomenclature, is disposed in axial alinement with main clutch shaft 20, which is provided with an axial bore inits rear end in which the reduced forward end 32 of the spline shaft is piloted. The rearward end of shaft 30 passes through the rear wall of the transmission casing l2a and is as usual mounted in bearings (not shown) in the casing.

Countershaft driving gear 22 meshes with a gear 40 rigid on countershaft 42, which has also rigidly connected to it, a gear 44 of the second speed train and other gears not shown since they are immaterial to this invention.

Gear 52 is mounted coaxial with spline shaft 30 on a bearing member 54 secured to the shaft so as to rotate with it. ,Said bearing has an integral flange 56 at one end and a separable flange 58 secured at the other end. Snap rings 59 or the like prevent axial movement of the bearing member 54 on shaft 30. Flanges 56 and 58 prevent axial movement of gear 52 with respect to bearlng member 54. Gear 52 is in constant mesh with countershaft gear 44, and is a part of the second speed train. It rotates freely on bearing member 54 unless locked to shaft 30 by means to be described.

Gear 52 is formed with an annular forwardreaching adjunct 24a similar to the adjunct 24 on gear 22. Adjunct 24a carries internal gearlike clutch teeth 26a and has an external conical friction surface 28a, corresponding to the elements 26 and 28 on adjunct 24 integral with gear 22. The body of gear 52and adjunct 24a with clutch teeth 26a and external friction cone 28a constitute one-half of a synchronizing coupling means to establish the transmission in second speed ratio.

In order to lock shaft 3|! either to the main clutch shaft 20 for direct, high speed driving, or to the gear 52 for second speed driving, a positive coupling element 60 is slidably keyed to shaft 30 between the gears 22 and 52. Coupling element 60 has external gear-like clutch teeth 52 at its forward end adapted to interlock with the internal gear-like clutch teeth 26 on the part 24 rigid with gear 22. External gear-like clutch teeth 62a on its rearward end are adapted to Interlock with internal gear-like clutch teeth a on part 24a rigid with gear 02. when coupling element 00 is moved forward teeth 62 interlock with teeth 26 with the result that shaft 20 is locked to the gear 22 and main clutch shaft 20 to couple the transmission in third speed. When coupling element 00 is moved rearward teeth 62a interlock with teeth 26a with the resuit that gear 52 becomes locked to shaft 00 so that the transmission is coupled in second speed.

Coupling element 60 is formed midway between its ends with a radially extending circumferential flange 64. Longitudinal openings spaced (in the form of the invention illustrated) 120 apart, extend from end to end.

Cooperating with the conical friction surface 20 of annular adjunct 24 rigid with gear 22 is an annular drum or cupped friction clutch element 00 having secured within its flange 02 an internally coned friction ring 04 adapted to be engaged with the conical surface 28 on adjunct 24 integral with gear 22. Another similar drum or cupped friction clutch element 00a carries secured within its flange 82, a similar friction ring 04a adapted to engage over the conical surface 28a on part 24a of gear 52. Each cupped friction clutch element 80 and 00a is of ring-like form and composed of flanges at right angles one to the other.

The friction clutch elements 80 and 80a are secured together by bars 90 that pass through the openings in slidable toothed coupling element 60 and its flange 64. The mid portions of the bars 90 are reduced and formed with checking surfaces 94 to coact with the beveled edges 12 of the openings in element 60 and flange 64 as means to resist meshing of the positive clutch elements until the friction elements have effected synchronization. When the positive cou-- pling element 60 is shifted toward the companion positive elements it carries with it the friction clutch elements by reason of a yieldable latch connection I00 carried by the coupling element 60, said latch engaging the reduced mid portions of the bars 90. The initial frictional engagement brings the checking surfaces into line with the edges of the openings, thereby resisting further longitudinal movement of the coupling element 00 until synchronization occurs in accordance with the well known mode of operation of inertia check synchronizers.

The means thus far described in outline are described in detail and claimed in the application of which this is a division.

In the tower-like riser I4a a shift lever II4a is fulcrumed. Said shift lever is constructed and arranged to engage selectively one or the other of the parallel shifter rails IIIa and 2:1 by causing its lower end to enter a notch in one rail or the other. Thereafter by rocking the lever fore and aft a shift may be made in the usual manner. In Fig. 3 the lower end I20a of shift lever 40 is shown engaged with a notch II2b formed in shift rail 2:: which is a part of the mechanism by which the muscular force of the operator applied to the shift lever is transmitted to the coupling element 60 in order to couple the synchronized second and third speed trains. Shift rail II Ia transmits the force exerted by the operator (when the lower end of shift lever II4a is engaged with said rail), to arm I60, which is secured to one end of a rock shaft I52 journaled in the casing I2a. Secured to the opposite end of said rock shaft is an arm I54 which may be connected to reverse or other unsynchronized transmission elements, not shown, since only the means for coupling the synchronized trains form the subject of the invention claimed herein.

The means shown for shifting coupling 60 comprises said shift rail 20, slidable in bearings in casing I 20, as shown in Fig. 3; a rock arm I06 adapted to be rocked by a longitudinal motion of said rail I I 2a, by means to be presently described; a hollow rock shaft I to which arm I56 is rigidly connected at one end; a rock arm I60 rigidly connected to the other end of the rock shaft, and shoes IBM and IBM hinged to said rock arms and grooved to engage the flange 64 of coupling 60 at diametrically opposite locations. Hollow rock shaft I50 is sleeved over rock shaft I52 and is rotatable independently of the latter. The arm I56 has two branches one of which, designated I 62, supports the pivoted shoe I56a and the other, I64, constitutes a part of the means whereby force is imparted to rock the arm I56 by longitudinal movements of shift rail II2a.

The branch I64 of arm I56 is elongated in a direction perpendicular to the center plane that includes the pivotal axis of said arm; and so parallel in general with shift rail II2a when the parts are in neutral position. To said branch I64 is secured, as by bolt I66, a member I60 having two relatively reversed but otherwise identical camming surfaces I10 and I12. The camming surfaces are separated, as shown, by a median pendant terminal I14.

A cam carrier such as saddle member I16, secured rigidly to shift rail 211, as by bolt I10, is provided at each end with spaced ears I80, I02. Camming rollers I04 and I06 are pivoted between the respective spaced ears on stout pivot pins I00 and I00. The pivot pins may be prevented from rotating within the supporting ears by any suitable device. The ends of the pins are shown as flattened and shouldered on one side as at I02 (Fig. 5) and the metal of the ears above the flattened and shouldered portions staked or swedged down into contact with the flattened surfaces and shoulders as shown, thus securing the pins so that they can neither rotate nor move endwise in the supporting ears.

As the transverse strains on shift rail II2a are severe while shifting into second and third speed ratios, rail II2a is reinforced by a short rail 200, which is secured in the casing, as shown in this embodiment, directly beneath and parallel with rail II2a. Rails H211 and 200 have opposed longitudinal grooves 202 and 204 constituting ball races for receiving bearing balls 206 which are retained properly spaced in the races by a retainer 200. Stop pins 2I0 may be disposed in groove or race 204 of rail 200 in order to prevent too great a displacement of the bearing balls lengthwise of the grooves. Four balls are shown spaced so that two are arranged normally substantially beneath each camming roller I04, I06, when the shift lever and connected parts are in neutral, as illustrated in Fig. 3.

The cam surfaces I10 and I12 on member I60 may be considered as divided each into three portionso, p and q. The portion 0 is curved in an are which approximates an arc of the same radius as the rollers I04 and I06. The portion p is a substantially plane surface and forms an angle of say 515 more or less with a plane perpendicular to the center plane of arm I56 that includes its pivotal axis. Said portion p therements 86 and 86d.

fore makes an angle of 515 withthe rail Ilia, when the parts are in neutral, since the latter is then perpendicularto the center line of arm I56. At each side of terminal I14 plane surface :2 merges into curved surface q, which forms an increasing angle with rail Ilia from the end of surface 1) to the tip 1.. v

When the parts are in neutral or starting posi tion as shown in Fig. 3 and in Fig.4 in solid lines, the rail I I2a is held in the said position of its range of endwise motion by the spring latch 2I2 which thenengages the middle one 'of the three detaining notches -2I4 in the rail. Atthis time,

of course, the shift lever may be'in the cross slot of the usual H-gate or equivalent, or it may have been moved laterally so as to place the end I26a in the notch IIZb of therail. Under these conditions both rollers are in contact with the plane of the shift lever forward (to the right as viewed in Fig. 3) thus moving rail N21: with rollers I84 and I86 rearward, causing the left-hand roller I86 as shown in Figs. 3, 4 and 4a to move rearward (to the left of said figures) and so causing the lever I56 to move clockwise thus rocking shaft I58 and attached arm I66 in the same sense of direction. The shoes I56a and I66a-on arms I56 and I66 that engage the circular flange 64 of coupling member 66 move said coupling member rearward carrying with it the friction clutch ele- The range of axial movement of the friction clutch elements from neutral position rearward is a few thousandths of an inch, and this distance is traveled before the roller I86 has reached the end of the plane cam surface p. In the first part of this movement sufficient frictional pressure is exerted between the friction cone surfaces due to the action of the cocking spring-detents I66 to cause the drum 86a to rotate with the gear 52 and cock the synchronizing parts, that is, bring the beveled checking surfaces 12 and 94 on the pins 96 and flange 64 into alinement in case the oil friction between the surfaces of the cones has not already done so. Continuing movement of the shift lever, acting through the parts described upon the checking surfaces 12 and 94, forces the conical friction surfaces together, squeezes out the oil film, and thus brings the positive coupling elements to equal velocities. Synchronizing is completed while the roller is in contact with the cam portion p, said roller moving faster than arm I56, and operating it with high mechanical advantage.

Further advance of the rail IIZa brings roller I86 into contact with the curved part q of the cam surface I12. The movement of arm I56 is then accelerated. The result is that, the resistance of the checking surfaces having been substantially removed, the coupling 66 advances rapidly toward its companion. As the roller I86 makes contact with the tip t of member I66 the other roller I84 moves against the pendant end I14 of arm I56 and swings said arm at the speed of the rail II2a causing the teeth 62a. of the positive clutch element 66 to slide rapidly into full engagement with the teeth 26a of its companion.

It will be observed that the rail I I 2a and rollers I84, I86 move progressively faster than the extremity of arms I56 from the neutral point until roller I84 catches up with the terminal member I14; after contact with said member I14 the roller and arm move at substantially the same speed. The course of travel of rollers and arm from neutral position to the end of the course when the teeth of the positive coupling elements become fully meshed may be considered as including four goals'or critical positions. Position I is the neutral position of the parts shown in Fig. 3 and in full line in Fig. 4. Position II is that assumed by roller and arm when the former has moved along the cam surface 9 far enough to have caused the cone friction elements to effect synchron zation. From position II to position III the roller has engaged the cam surface q and moved arm I56 at rapidly increasing speed, pushing the slidable positive clutch element rapidly toward its companion, the friction elements having been released when synchronization occurred. Position IV is at the end of the travel of rollers and arm I56 when detent latch 2|! has engaged the forward notch 2I4 and the positive clutch jaws are fully meshed. Movement of both roller I86 and arm I56 from position III to position IV is, as before stated, at the same speed since during that movement roller I84 bears against terminal member I14.

During the movement of the roller from position I to position II it will be apparent that a large quantity of force is applied to the arm I55 and consequently to the coupling 66 to effect synchronization because of the high mechanical advantage afforded by the inclined cam surface 1). The advantage increases, it is apparent, the further the roller moves along that surface toward the surface q. The surface p is made long enough to allow for wear in the clutch surfaces. When the surfaces are new travel of roller I86 along cam surface p for less than half the distance from neutral to the end of that surface accomplishes synchronization. The remainder of this surface is available for synchronization after wear has made necessary increased movement of the friction clutch drum from neutral.

The operation of shifting from neutral to third speed ratio is the same as that described for shifting into second, the movements being reversed or in the opposite sense. In moving the parts from second or third speed ratio back to neutral the advance roller in the return movement will move.

arm I56 back by engaging the cam surface q which is on the same side of the end member I 14; and when neutral position is attained both rollers will be respectively in substantial contact with the respective surfaces p as illustrated.

It will be apparent that by an even movement imparted by a normal effort of the driver to shift lever lI4a when it has been selectively interlocked with rail I I2a, the friction clutch elements will be forced into engagement with an augmenting force greatly exceeding that applied to the shift lever; that after synchronism has been attained the checking surfaces are displaced as is usual in transmissions of the inertia check type and the slidable coupling moved with accelerating speed into interlocking engagement with its companion.

I claim:

1. A lever adapted to effect engagement and disengagement of a clutch; movable camming means; means for guiding, the camming means in a straight path; said lever having a cam surface in the path of the camming means contoured to cooperate with the movable camming means to move the lever with high mechanical advantage during the early part of its movement, and another surface cooperating with the camming T5 means during the latter partof its movement to accelerate the movement of the lever.

2. A supporting casing, a lever adapted to effect engagement and disengagement of a clutch; slidable camming means guidable in suitable bearing means in the casing frame for moving said lever; a stationary reinforcing member at one side of and extending parallel with the direction of movement of the camming means for the full length of movement thereof and arranged to resist the direct reaction force of the slidable camming means while the latter is moving the lever; said lever having'a cam surface in the path of movement of the camming means.

3. A lever adapted to effect engagement and disengagement of a clutch; camming means adapted to engage said lever; a slidable shift rail for supporting and guiding said camming means; a stationary reinforcing member having a straight surface parallel with the shift rail on the side opposite that on which the camming means is mounted and coextensive with the amplitude of movement thereof; said shift rail having bearing engagement with the reinforcing member.

4. A combination as defined in claim 3, with roller bearing elements between the shift rail and reinforcing member.

5. A lever adapted to effect engagement and disengagement of a clutch, said lever having a transverse member extending parallel with the plane of movement of the lever and having a cam surface, a slidable camming means and means for guiding said camming means into operative engagement with the cam surface of the lever, said cam surface having a contour formed to cooperate with the slidable camming means so as to move the lever with high mechanical advantage during the early part of its movement and to accelerate the movement of the lever at the expense of mechanical advantage during the latter part of its movement.

6. A lever adapted to effect engagement and disengagement of a double ended synchronizing clutch, said lever having a transverse member extending on opposite sides of the lever parallel'to the plane of movement of the lever, the transverse member having cam surfaces diverging toward the ends of the transverse member and away from the lever fulcrum at different angles in different parts of its length, and camming means movable to engage said cam surfaces, said cam surfaces being of a contour to cause the camming means to move said lever with a high mechanical advantage during the early part of the movement of the camming means in either sense of direction and to accelerate the movement of the lever at the expense of mechanical advantage during the latter part of the movement of the camming means in either sense of direction.

7. A lever adapted to effect engagement and disengagement of a clutch, said lever having a transverse member extending on opposite sides sides of said lever, said cross member having relatively reversed cam surfaces one on each side of the center thereof, said cam surfaces diverging oppositely toward the ends of the cross member and away from the fulcrum of the lever, a central projection extending from the cross member midway of said diverging cam surfaces, and a cammlng member slidable in a straight path in both senses of direction, said camming member having two spaced apart roller camming elements disposed on opposite sides of said projection and spaced therefrom in neutral position of the lever.

9. Means for operating a synchronizing clutch comprising a slidable shift rail, a manual shift lever engageable with the shift rail whereby said shift rail may be actuated; camming means on the shift rail; a pendent lever arm having cam surfaces arranged in the path of movement of the camming means, and means movable with the pendent lever arm for effecting engagement of a clutch; a fixed reinforcing member parallel with said shift rail, said reinforcing member having a length at least coextensive with the extent of movement of the camming means and bearings between said rails and reinforcing member to receive the reaction of the camming means.

EARL A. THOMPSON. 

